We recently received prototypes of the new Grand Bois “Lierre” (Ivy) 650B x 36 mm tires. A few readers already spied them at the Oregon Handmade Bicycle Show, mounted on the bike displayed at the Bicycle Quarterly stand.

When 650B first became a popular wheel size again, many bikes were designed for the excellent 650B x 38 mm Mitsuboshi “Trimline” tires. Mitsuboshi left the bicycle tire market more than five years ago, leaving many 650B riders scrambling for medium-width tires. With similar width and tread thickness as the Mitsuboshi, the “Lierre” is a welcome addition to the 650B market.

Like all Grand Bois tires, the “Lierre” was designed to offer excellent comfort and performance, combined with good longevity. The prototype’s tread is a bit thicker than the production version will be, so we do not have accurate weight and riding impressions yet. The width is a true 36 mm, and probably will grow by a millimeter or so over time. Thus, it is right in the middle between the “Cypres” 650B x 32 mm and the “Hetre” 650B x 41 mm tires.

The tread pattern is inspired by a 1950s Hutchinson tire. The Grand Bois “Lierre” will be available in late December 2010 or early January 2011.

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About Jan Heine, Editor, Bicycle Quarterly

I love cycling and bicycles, especially those that take us off the beaten path. I edit Bicycle Quarterly magazine, and occasionally write for other publications. One of our companies, Bicycle Quarterly Press publishes cycling books, while Compass Bicycles Ltd. makes and distributes high-quality bicycle components for real-world riders.

No current plans for 700C tires wider than the 31-33 mm-wide Cypres. 700C wheels with wide tires make the bike less nimble – see the testing of wheel sizes in the Spring 2010 Bicycle Quarterly – so Grand Bois prefers 650B wheels for wide tires.

Yes, it’s not that big 650B tires aren’t awesome. It’s that 66cm+ 650B frames aren’t awesome. In that respect, it’s a “problem solver” item, these 700×35 Grand Bois tires LeafS. is asking for. It’s a tough “problem” to get rid of though for those of us that have it. The irony is that we need the high volume most. In this case Grand Bois 700×35 tire would only be compared with other 700×35 tires. To these riders the 31-33mm Cypres represents the smallest tire they dare ride on good roads! Rough roads? Forget it.

Are your concerns about large 650B frames aesthetic or functional? It’s pretty clear that wheel size should NOT scale with frame size, because the gyroscopic forces affect how the bike handles. (See the Spring 2010 issue of Bicycle Quarterly for details.) A 650B x 42 wheel with fenders is as large as a 700C x 25 mm wheel without fenders, and few people argue that large racing bikes “aren’t awesome.” If you want to fill up the large empty space on a 66+ cm frame, consider adding triangulation with two lateral tubes (like a mixte). For a tall, heavy rider, this may be a good idea anyhow to make the frame stiff enough. (I’d stay away from oversize tubing, though, otherwise, you might get a frame that is too stiff.) For an example, see

A different issue are riders who already have 700C bikes. It would be nice to offer them wider high-performance tires. However, tire molds are very expensive, and Grand Bois allocates the money where it will do the most good.

Whether tread patterns are cosmetic for riding on pavement is hard to say. The proponents of slick tires (no tread) rightly point out the bicycles don’t hydroplane, but they overlook the fact that you usually slide not on water, but on sand or oil. Can a tread pattern help by increasing the surface pressure and providing cavities for sand grains? I don’t know. About the “Lierre” tire’s zigzag tread pattern, it is a copy of an old tread pattern from the 1950s. If there was any specific thinking behind this pattern, it has been lost in the half-century since. The Grand Bois Hetre’s tread pattern also is a copy of an old tire, but I wonder whether the pattern contributes to the remarkable flat resistance of the Hetres. The grooves are tapered, and it may be hard for glass to stick in them, as they get ejected with every wheel revolution. (Or perhaps it’s just the relatively low pressure of wide tires that make it harder for obstacles to penetrate the casing?)

If your tread blocks get too tall compared to their width and length, then you effectively have knobbies, and your tread blocks squirm, slowing you down. Of course, on sand or gravel, well-designed treads help the tire to “hook up” with the surface. My overall conclusion is that fine tread patterns don’t do any harm, and they may do some good.